As the air conditioning system of the vehicle, generally, the air conditioner and blower are employed. To control such a system, there are equipped a main switch to start/stop the air conditioner and a change-over switch to change the airflow of the blower. For this airflow change-over switch, a slide switch is employed mainly. While this airflow change-over switch has a stop position to stop blowing, if the air conditioner is in operation in spite of the switch being at the stop position, there results in such an inconvenience that a cooling coil is frosted. Therefore, when stopping the blower, the air conditioner must be stopped surely.
As apparent from the foregoing description, in order to stop surely the air conditioner at the time of stopping the blower, a composite switch was employed in the prior art which is made up by coupling together the main switch and the airflow change-over switch.
In more detail, the conventional composite switch will be described with reference to FIGS. 5 and 6.
In FIG. 5 illustrating the conventional composite switch, 1 is the main switch and 2 is the change-over switch. This main switch 1 is the so-called push-push type switch and employed for start/stop of the air conditioner of the vehicle. An operation member 3 of the main switch 1 has a heart-shaped grooved cam 3a, against the inner face of which a ball 4 is pressed by a spring (not shown). The operation member 3 is normally projecting in the A direction by the force of the spring (giving the off state). As the operation member 3 is pushed in the B direction, a contact turns on and, during this time, the ball 4 traces the inner face of the grooves cam 3a. When the ball 4 stops at a lock position (the .alpha. position) inside the grooved cam 3a, the operation member 3 is held there, so that the contact is also held in the on state. Then, if the operation member 3 is pushed further from the above state, the ball 4 departs from the lock position .alpha. and the operation member 3 returns in the A direction owing to the spring force thereby resulting in the switch-off state. In the foregoing structure, the ball 4 is designed so that it can move only in the right/left directions in the drawing within a slot 5a of a control member 5.
With respect to the change-over switch, it is made in the form of a frame by a case 6 of insulating material and a cover 7 of metal plate. Inside the frame a working member 8 made of insulating material is slidable freely. This working member 8 holds a sliding contact 8a, whereas on a surface 6a of the case 6 plural fixed contacts (not shown) are secured. Further, into the working member 8 a tip 9a of an operation lever 9 is projecting. This operation lever 9 is pivotable about a support point 10.
As the operation lever 9 is turned in the C direction, the working member 8 moves leftward in the drawing and the sliding contact 8a contacts with a left side contact, whereby the airflow caused by the blower is switched to a higher stage. From this stage, as the operation lever 9 is turned gradually in the D direction, the working member 8 moves in the right direction in the drawing. During this movement the sliding contact 8a comes successively into contact with other fixed contacts to change to an airflow-decreasing position. At the position where the operation lever 9 is turned up to the maximum in the D direction, the airflow terminates. At the same time, the working member 8 pushes an end portion 5b of the control member 5. While the control member 5 is positioned normally in the state shown in FIG. 5 owing to a spring, when pushed by the working member 8 it moves in the right direction in the drawing (see FIG. 6). Thus, the slot 5a of the control member 5 pushes the ball 4 in the right direction. Accordingly, even if the operation member 3 of the main switch 1 is locked at the B direction position thereby giving the on state of the contact, due to the foregoing movement of the control member 5 the ball 4 gets out of the lock position .alpha. of the grooved cam 3a, the operation member 3 returns immediately in the A direction, the main switch 1 turns off, and the air conditioner stops.
In the foregoing conventional composite switch, when the working member 8 of the change-over switch 2 moves in one direction the lock member 4 of the main switch 1 is moved forcedly in the releasing direction, whereby the switch 1 is turned off. That is, the operation member 3 of the main switch 1 itself is caused to return completely to the off direction. Accordingly, when to start again the air conditioner, the operation member 9 of the change-over switch 2 must be operated to commence blowing and the operation member 3 of the main switch 1 must be pushed again. These operations are troublesome during the vehicle driving and a driver is apt to forget to push the main switch 1 and other manipulation.
In addition, because the mechanical operation is performed to release the on state of the main switch 1, a mechanism for releasing the locked main switch 1 becomes complicated and there is a fear that the operation becomes incomplete.
Further, because the conventional composite switch has no means for indicating the operation state of the main switch 1, it sometimes becomes impossible to confirm the operation state and the like of the air conditioner, for example, during the night driving of the vehicle.